Daniel is 4 times as old as Gabriela and is also 6 years older than Gabriela. How old is Gabriela?
Explanation: We can use the given information to write down two equations that describe the ages of Daniel and Gabriela. Let Daniel's current age be $d$ and Gabriela's current age be $g$ $d = 4g$ $d = g + 6$ Now we have two independent equations, and we can solve for our two unknowns. Since we are looking for $g$ , and both of our equations have $d$ alone on one side, this is a convenient time to use elimination. Subtracting the second equation from the first equation, we get: $0 =$ $4g$ $-$ $ (g + 6)$ which combines the information about $g$ from both of our original equations. Solving for $g$ , we get: $3 g = 6$ $g = 2$.